diff --git a/flix/mavlink.cpp b/flix/mavlink.cpp
index 0803e14..992e5a7 100644
--- a/flix/mavlink.cpp
+++ b/flix/mavlink.cpp
@@ -18,7 +18,7 @@ Rate telemetryFast(10);
 Rate telemetrySlow(2);
 
 bool mavlinkConnected = false;
-String mavlinkPrintBuffer;
+static String mavlinkPrintBuffer;
 
 void processMavlink() {
 	sendMavlink();
diff --git a/flix/parameters.cpp b/flix/parameters.cpp
index 6955c3e..1aa9f5d 100644
--- a/flix/parameters.cpp
+++ b/flix/parameters.cpp
@@ -45,7 +45,7 @@ struct Parameter {
 	void setValue(const float value) { if (integer) *i = value; else *f = value; };
 };
 
-Parameter parameters[] = {
+static Parameter parameters[] = {
 	// control
 	{"CTL_R_RATE_P", &rollRatePID.p},
 	{"CTL_R_RATE_I", &rollRatePID.i},
diff --git a/flix/rc.cpp b/flix/rc.cpp
index 7433c72..8db1509 100644
--- a/flix/rc.cpp
+++ b/flix/rc.cpp
@@ -6,7 +6,7 @@
 #include <SBUS.h>
 #include "util.h"
 
-SBUS rc(Serial1);
+static SBUS rc(Serial1);
 int rcRxPin = -1; // -1 means disabled
 
 uint16_t channels[16]; // raw rc channels
diff --git a/flix/wifi.cpp b/flix/wifi.cpp
index a659445..023b519 100644
--- a/flix/wifi.cpp
+++ b/flix/wifi.cpp
@@ -22,11 +22,11 @@ int wifiMode = W_AP;
 int wifiLongRange = 0;
 int udpLocalPort = 14550;
 int udpRemotePort = 14550;
-IPAddress udpRemoteIP = "255.255.255.255";
-WiFiUDP udp;
+static IPAddress udpRemoteIP = "255.255.255.255";
+static WiFiUDP udp;
 
-ESPNOWSerial espnow(NULL, 0, WIFI_IF_AP);
-ESPNOWSerial espnowBroadcast(ESP_NOW.BROADCAST_ADDR, 0, WIFI_IF_AP);
+static ESPNOWSerial espnow(NULL, 0, WIFI_IF_AP);
+static ESPNOWSerial espnowBroadcast(ESP_NOW.BROADCAST_ADDR, 0, WIFI_IF_AP);
 int espnowChannel = 6;
 
 void setupWiFi() {